Urinary morbidity following radioactive seed implantation for prostate cancer is common. Alpha-blockers with or without steroids following prostate implantation have been used routinely to reduced these symptoms; however, there are no randomized trials examining the efficacy of this treatment. This trial was designed to determine the efficacy of prophylactic tamsulosin in reducing urinary signs and symptoms following prostate seed implantation.

Materials and Methods

Patients were eligible for this study if they were eligible for treatment of their prostate cancer with seed implants only.

Patients already receiving tamsulosin or other alpha-blockers were excluded from the study.

All patients received implantation with I-125 seeds using a peripheral loading technique and all patients received a CT scan 4 weeks after the implant to determine radiation dosimetry.

Baseline American Urologic Association (AUA) score for urinary symptoms were obtained on all patients.

All patients started either tamsulosin or placebo 4 days prior to the implantation to achieve steady-state levels of medication.

Following implantation, AUA scores were assessed every week for 8 weeks. Patients reached the primary endpoint and were censored from the study if they developed increased urinary symptoms, urinary retention, or chose to drop out from the study.

Results

118 patients were entered into the study.

The median age was 64.5 years (range 44-82).

Median PSA was 6.1.

85% of patients had a Gleason Score of 6 or 7.

88% of patients were stage T1c.

>90% of patients had a prostate volume of <60cc.

There was no difference in the two treatment arms with regards to baseline AUA score, prostate volume, number of needles used, number of seeds used, total activity of the implant, or post-operative dosimetry.

With regards to the number of patients completing all 8 weeks of therapy, there was no difference between the two arms.

There was no difference between the two arms with regards to the number of patients stopping the study due to symptoms; however, there was a non-significant difference with regards to number of patients stopping due to urinary retention (16.7% for placebo vs. 10% for tamsulosin).

There was no difference in AUA score between the two groups until week 5, at which time, a signficant difference was seen in average AUA score (p=0.03).

Author's Conclusions

A dose of 0.8 mg qd of tamsulosin is safe for prophylaxis.

There is no difference in urinary retention rates with the addition of prophylactic tamsulosin; however, by week 5, there was a difference in urinary symptoms.

A current study is ongoing comparing the effectiveness of prophylactic tamsulosin and steroids compared to tamsulosin alone for patients undergoing prostate seed implants.

Clinical/Scientific Implications

The findings of the current study indicate that there may be some symptomatic relief with addition of prophylactic alpha-blockers such as tamsulosin to prostate seed implants. This improvement in symptoms is quite modest, and the study does not compare the symptomatic relief achieved with prophylactic tamsulosin compared to the initiation of tamsulosin only for patients experiencing significant symptoms. Given the lack of benefit with regards to urinary retention in these patients, the use of prophylactic tamsulosin for all patients undergoin prostate seed implants cannot be recommended, despite the mild improvement in urinary symptoms seen in this study.